GENUS 73. 



THISTLE FAMILY. 



5 01 



2. Thelesperma intermedium Rydb. 

 Stiff Thelesperma. Fig. 4520. 



Thelesperma intermedium Rydb. Bull. Torr. Club 

 27 : 631. 1900. 



Perennial from a deep woody root and slen- 

 der rootstocks ; stem rigid, usually much 

 branched, i-i$ high. Leaves usually numer- 

 ous, i\'-2' long, bipinnately divided into entire, 

 rigid, linear segments, but less compound than 

 those of the preceding species; outer bracts of 

 the involucre lanceolate-subulate, usually much 

 shorter than the inner ones, which are united 

 to about the middle: rays and achenes similar 

 to those of the preceding. 



In dry soil, on plains, Nebraska and Wyoming 

 to Colorado and New Mexico. In our first edition 

 included in T. ambiguum A. Gray, of the South- 

 west. June-Aug. 



3. Thelesperma gracile (Torr.) A. Gray. 

 Rayless Thelesperma. Fig. 4521. 



Bidens gracilis Torr. Ann. Lye. N. Y. 2: 215. 1827. 

 T. gracile A. Gray, Kew. Journ. Bot. i : 252. 1849. 



Perennial from a deep root; stem rigid, branched, 

 i-3 high, the branches nearly erect. Leaves rigid, 

 erect or ascending, 2'-3' long, pinnately or bipin- 

 nately divided into linear segments, or the upper 

 linear and entire; heads 6"-io" broad; rays usually 

 none, sometimes present and 2"-3" long ; outer bracts 

 of the involucre 4-6, oblong or ovate, mostly ob- 

 tuse, very much shorter than the inner ones, which 

 are united to the middle or beyond ; disk yellow or 

 brownish; outer achenes slightly papillose; pappus 

 awns longer than the width of the summit of the 

 achene. 



On dry plains, Nebraska and Wyoming to Texas, 

 northern Mexico and Arizona. May-Aug. 



74. GALINSOGA Cav. Icon. 3: 41. 1794. 



Annual branching herbs, with opposite, mostly petioled, dentate or entire leaves, and 

 small peduncled heads of both tubular and radiate flowers, terminal and in the upper axils. 

 Involucre hemispheric or broadly campanulate, its bracts in 2 series, ovate, obtuse, mem- 

 branous, striate, nearly equal, or the outer shorter. Receptacle conic or elongated, its thin 

 chaff subtending the disk-flowers. Ray-flowers white or red, pistillate, fertile, the rays 4 or 

 5, short. Disk-flowers yellow, perfect, the corolla 5-toothed. Anthers minutely sagittate at 

 the base. Style-branches tipped with acute appendages. Achenes angled, or the outer ones 

 flat. Pappus of the disk-flowers of several short laciniate or fimbriate scales, that of the 

 ray-flowers of several or few short slender bristles, or none. [Named in honor of M. M. 

 Galinsoga, superintendent of the Botanic Gardens at Madrid.] 



About 5 species, natives of tropical and warm temperate America, the following typical. 



